在纳米晶Co－Mo／Ni复合电极上的析氢反应

Abstract

采用复合电镀的方法将不同球磨时间制备的高催化活性的纳米晶Ｃｏ－Ｍｏ合金粉直接镀在电极表面，用稳态极化曲线及交流阻抗技术测试了这些电极析氢的电化学活性，并用Ｘ射线衍射、透射电镜及Ｘ射线光电子能谱、扫描电镜监测了Ｃｏ－ＭＯ合金粉的物相结构、晶粒尺寸和复合镀层的成份、形貌，实验结果表明，Ｃｏ－Ｍｏ纳米晶合金粉有较高的析氢催化活性。球磨使钴钼粉合金化成为纳米晶，一方面增加了复合镀层的真实表面积，另一方面由于纳米晶合金具有高比例的表面活性原子，致使析氢活化能降低，加快了析氢反应，研究表明在不太高温度下，电化学脱附的活化能和整个析氢反应的活化能一致。说明电化学脱附为速度控制步骤。

The electrochemical behaviours of the hydrogen evolution reaction(HER) at electrodes prepared by composite coating of nanocrytstalline Co-Mo alloy particles formed by ball milling on nickel base has been sludied by using sleady-state polarization and ac impedance techiu ques.The microstructure and the size of the nanocrystals of Co- Mo alloy and the morphology of the composite-coating surface of the electrodes are measured by XRD, TEM and SEM. Results show that the nanocrystalline Co-Mo alloys prepared by high energy ball milling has high electrocatalytic activity for HER. The electrocatalytic activity for the HER is enhanced and the energy of activation for HER is decreased with increasing milling time. They are attributed to the increase in the real surface areas of the electrode and high proportion of active atoms on the surface of electrodes. The temperature study show that the energy of activation of electrodesorption is the same as the energy of activation of the overall reaction. The reaction rate of HER on the electrodes is proved to be controlled by electrodesorption.